In a 10x10 grid (occasionally another size), there are 10 ships hidden, as follows:

Four ships which each occupy a single space in the
grid

Three two-unit-long ships

Two three-unit-long ships

One four-unit-long ship

In the grid, the one-unit ships are represented as circles, while the longer ones are represented by U-shapes at each end, and squares for the middle pieces. (So you don't know whether a square is part of a ship running horizontally or vertically.)

The ships are all straight, each lying in a single row or column of the grid.

These ships are all arranged in the grid so that no two ships touch, not even diagonally.

For each row and each column, you are told how many units of ship pieces lie in it.

Usually you are initially provided with the contents of a few squares -- just enough to make the solution unique.